The Domain Name System [“DNS”] allows human meaningful names to be associated with the numerical internet protocol [“IP”] addresses of clients, servers, or other resources on the internet. For example, the domain name www.example.com may be associated with 208.77.188.166. Domain names are mapped and indexed by name servers. Each name server is authoritative or responsible for indexing clients, servers, or other resources within its zone of authority. When a user requests a resource by domain name, a DNS resolver identifies the request. If the IP address for the requested resource is not available in its cache, the resolver initiates a query to a name server. The DNS resolver's query includes a transaction identifier. The name server's reply may also include the transaction identifier to identify the response as having come from the name server queried by the DNS resolver. If a malicious attacker can respond to a DNS resolver's request before the real name server can, the malicious attacker can direct the user to a different client, server, or resource than was intended. This opens possibilities of identity or data theft or other malicious activities.